Question: Simplify the following expression: $t = \dfrac{z}{2} - \dfrac{5z}{3}$
Solution: In order to subtract expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $2$ and $3$ $\lcm(2, 3) = 6$ $ t = \dfrac{3}{3} \cdot \dfrac{z}{2} - \dfrac{2}{2} \cdot \dfrac{5z}{3} $ $t = \dfrac{3z}{6} - \dfrac{10z}{6}$ $t = \dfrac{3z -10z}{6}$ $t = \dfrac{-7z}{6}$